This is VERY interesting and informative.

[josh green]

all of that theory changes a bit in drifting, where you see the hood shimmed up in the rear.

with drifting you get two benefits to shimming the hood.
1. while waiting in staging for your runs, the engine bay vents better with the hood shimmed.
2. when sideways, the airflow going across the hood pulls air from the trailing edge instead of hitting the windshield and creating high pressure.

I believe that all that was said is still valid for drifting. I looked up some drift cars, D1GP cars and I didnt see 1 car with a propped hood. I am sure that proper ducting of the radiator would provide air flow over the radiator just as well. Majority of the cars have the vented hoods like what is spoken of in the post.